With the development of science and technology, head up display (HUD) systems are increasingly used in automobiles. The important driving information, such as speed, engine revolution, fuel consumption, tire pressure, navigation and external smart device information, may be displayed by vehicle HUD system in real time on the front windshield within the driver's vision field, so that the driver can catch sight of the driving information without hanging his head, and his distraction from the road ahead is accordingly avoided. Meanwhile, the driver need not interchange his eyesight from observing the road ahead to the dashboard nearby. Thus, eye strain is avoided, driving safety is greatly enhanced, and driving experience is improved.
At present, the existing vehicle HUD system is a single-layer virtual image display system which projects the information as characters and/or diagrams to the front windshield by way of optical reflection principle, and the imaging position of the characters and/or diagrams is determined by the optical system. Generally the image is formed a few meters in front of the vehicle
In addition, the existing vehicle HUD system can only form a plane image rather than a stereoscopic image. Furthermore, the existing vehicle HUD system is incapable of adjusting the imaging position.
It is noted that the information disclosed in the foregoing background section is merely used for those skilled in the art to enhance their understanding of the background of the present disclosure, and therefore, some other information which is not known to those skilled in the art as prior art may be involved in this section.